Abstract: Objective:To study the protective effect of curcumin on oxidative stress and inhibition of cardiomyocyte apoptosis induced by overtraining in rats. Methods:Sixty male Wistar rats of 7 weeks old were randomly divided into control group (C group,12),overtraining group (OM group,24),curcumin+overtraining group (COM group,24) after adaptive feeding and training. The C Group did not undergo any training. Rats in OM and COM group underwent 8-week incremental load swimming training. During the training,the COM group was given 200 mg/(kg·d) of curcumin in the volume as 5 mL/kg,and the other groups were given an equal volume of 0.5% carboxymethylcellulose. 24 hours after the last training,myocardial histopathological changes were observed by light microscopy;serum testosterone (T),corticosterone (Cor) and cardiac troponin I (cTnI),cardiomyocyte apoptosis level,the expression level of nuclear factor E2 related factor 2 (Nrf2),heme oxygenase-1 (HO-1),B cell lymphoma-2 protein (Bcl-2) and Bcl-2 related X protein (Bax) in myocardium were detected;myocardial total antioxidant capacity (T-AOC),superoxide dismutase (SOD) activity,malondialdehyde (MDA) concentration were also detected. Results:The results showed that after 8-week incremental load swimming training,the myocardial tissue structure of the C group was normal under light microscope;histopathological changes were observed in the OM group;the COM group was relieved compared with the OM group. Compared with the C group,serum corticosterone and cTnI,cardiomyocyte apoptosis level,the expression level of proapoptotic Bax,MDA concentration in OM group were increased (p<0.01);serum testosterone,myocardial T-AOC and SOD activity (p<0.01),the expression level of HO-1 and anti-apoptotic Bcl-2 (p<0.05) were lower;Nrf2 expression level did not change significantly (p>0.05). Compared with the OM group,serum corticosterone,cardiomyocyte apoptosis level,the expression of Bax (p<0.01),serum cTnI,myocardial MDA concentration (p<0.05) were decreased in the COM group;serum testosterone,the expression levels of Nrf2 and Bcl-2,myocardial T-AOC and SOD activity (p<0.01),the expression levels of HO-1 (p<0.05) were increased. The trends of T/Cor and Bcl-2/Bax between groups were consistent with the changes of T and Bcl-2,respectively. Conclusion:Curcumin can up-regulates expression of Nrf2 and HO-1,effectively alleviates oxidative stress induced by overtraining,thereby increasing Bcl-2 expression,decreasing Bax expression,inhibiting cardiomyocyte apoptosis and protecting cardiac tissue structure and function properly.